A chuck device having a one-step lock and release mechanism for conveniently coupling a power bit to a drill having a Jacobs-style chuck. The chuck device includes a body having a centrally-positioned bore which is adapted to receive the power bit shank. The power bit shank includes a circumferentially-extending groove which is positioned inside the bore. The body has an inclined cam channel which includes an aperture for communicating with the bore. The body further includes a longitudinally-extending slot communicating with the inclined cam channel. A detent ball is disposed within the inclined cam channel for partial penetration through the aperture for engaging the circumferentially-extending groove of the power bit shank. A spring having an end encircles the body where the end is slidably positioned within the slot for biasing the detent ball rearwardly along the inclined cam channel during the unlocking and withdraw of a power bit from the chuck device. The position of the spring is confined on the body by a retaining ring positioned proximate to the inclined cam channel and by a sleeve which encircles a portion of the body. The retraction of the sleeve in a rearward direction compresses the spring and rearwardly biases the spring end within the slot for movement of the detent ball from locking engagement to the circumferentially-extending groove. Release of the sleeve permits the expansion of the spring and the biasing of the sleeve and detent ball in a forward direction for locking engagement to a power bit.